Commuting by SS/FG

Is that mainly flat? I live in the Arun valley in sussex which is quite hilly, I can do 3.5 miles in 10 minutes with 3 moderate hills. I have been commuting for a week so far and i'm running 44x18, is that a good setup?

48x18 gets me to and from work, but then, so does 42x16 (both around 70" or thereabouts), in mid sussex/the weald.

As an owner and rider of geared bikes too it always surprises me what youcan grind or honk your way up when you've only got one gear.